1. Field of the Invention
The present invention relates to a stand apparatus used when a working implement such as a front loader is coupled to and uncoupled from a vehicle such as a tractor.
2. Description of the Related Art
(I) A conventional stand apparatus for keeping a front loader standing by itself on the ground is disclosed in Japanese Utility Model Publication Kokai No. 1990-102908, for example. According to this apparatus, a vehicle body includes mast mounts arranged at opposite lateral positions thereof, and fight and left masts pivotally supporting proximal ends of loader booms have lower ends thereof removably attached to the mast mounts, respectively. The masts are interconnected in intermediate positions thereof by a connecting member. Each mast pivotally supports, in a lower portion thereof, a proximal end of a stand member through a cross axis. The stand member is pivotable between an operative position having a ground engaging end thereof contacting the ground and a contained position with the ground engaging end directed upward. The apparatus includes an operative and contained position retaining device for retaining the stand member in each of the operative position and contained position.
When uncoupling the front loader from the tractor, a bucket cylinder must be operated to cause the booms to pivot about forward ends thereof, thereby to raise the lower ends of the masts above the front wheels. The stand apparatus also contributes to raising of the masts at this time. The smaller the masts are, the easier is the operations to couple and uncouple the front loader. This requires the lower ends of the masts to be connected at a relatively high level to the mast mounts. The stand members are longer where the lower ends of the masts are connected at a relatively high level to the mast mounts than where the lower ends; of the masts are connected at a low level. When such long stand members are swung upward to the contained position extending along the masts, the ground engaging ends project a large extent upward and could obstruct the driver's view during an earth moving operation.
(II) In the working implement coupling apparatus noted above, control valves and control levers for controlling boom cylinders may be mounted on the masts with a view to simplification of hydraulic piping or because of a restriction as to installation space. In this case, the driver in the cab provided rearwardly of the masts must operate the control levers from beginning to end of a coupling or uncoupling operation. It is therefore desirable that the masts move a minimal amount forward during the coupling or uncoupling operation. For this purpose, the lower ends of the stand members should be placed as close to the ground as possible when fixing the stand members to the masts.
Further, the tires generally used on tractors include farm tires suited for operations on soft farmland, and turf tires for use on grassland. Where the rim diameter is the same, farm tires with high lugs usually have a larger diameter than turf tires. Consequently, depending on the type of tires attached to the vehicle body, the height of the vehicle body is variable during an operation to couple or uncouple the working implement.
As noted above, the height of the vehicle body is not always the same. In order that the stand members may be fixed to the masts to extend forwardly and downwardly, the fixed position of the stand members relative to the masts must be determined according to the height of the vehicle body having turf tires (i.e. minimum height). For, if the fixed position of the stand members were determined according to the height of the vehicle body having farm tires (i.e. maximum height), the stand members could not be fixed because of the lower ends of the stand members contacting the ground when farm tires are replaced with turf tires.
However, if stand members suited to the height of the vehicle body having turf tires are used also when farm tires are attached, the lower ends of the stand members fixed to the masts will be distanced from the ground by the difference in vehicle height. When the working implement is uncoupled in this state, the masts will tilt a considerable amount forward until the lower ends of the stand members touch the ground. Consequently, the control levers attached to upper positions of the masts will move far from the cab provided rearwardly of the masts. This inconveniences the driver operating the control levers in the cab.
(III) Another disadvantage is that the driver must hold the stand members extending forwardly and downwardly with hands when fixing the stand members to the masts. Thus, the operation to fix the stand members to the masts is troublesome and difficult.